[Pratt Parser] Refactor worker methods and parse unary operator chains iteratively.

- Extract helper methods (`ParseTernary`, `ParseSelectorChainTail`, `ParseUnaryOpsChain`, `ParseIdentOrCall`, `ParseNegativeIntLiteral`, `ParseNegativeDoubleLiteral`, `BuildBinaryCall`) to reduce the size of the call stack frames
- Process prefix unary operator chains (`!`, `-`) iteratively in `ParseUnaryOpsChain` to reduce stack growth on deep chains.

PiperOrigin-RevId: 953546973

Author: dmitriplotnikov

parser/internal/BUILD

@@ -91,6 +91,7 @@ cc_library(
         "//internal:strings",
         "//parser:options",
         "//parser:parser_interface",
+        "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/base:nullability",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/status:statusor",

parser/internal/pratt_parser_test.cc

@@ -723,6 +723,18 @@ std::vector<TestCase> GetParserTestCases() {
               )^#4:Expr.Call#
             )",
       },
+      TestCase{
+          .source = "(((10 - 3) - 2))",
+          .expected_ast = R"(
+              _-_(
+                _-_(
+                  10^#1:int64#,
+                  3^#3:int64#
+                )^#2:Expr.Call#,
+                2^#5:int64#
+              )^#4:Expr.Call#
+            )",
+      },
       TestCase{
           .source = "1 + 2 * 3 - 1 / 2 == 6 % 1",
           .expected_ast = R"(
@@ -747,6 +759,30 @@ std::vector<TestCase> GetParserTestCases() {
               )^#10:Expr.Call#
             )",
       },
+      TestCase{
+          .source = "(1 + (2 * 3) - (1 / 2)) == (6 % 1)",
+          .expected_ast = R"(
+              _==_(
+                _-_(
+                  _+_(
+                    1^#1:int64#,
+                    _*_(
+                      2^#3:int64#,
+                      3^#5:int64#
+                    )^#4:Expr.Call#
+                  )^#2:Expr.Call#,
+                  _/_(
+                    1^#7:int64#,
+                    2^#9:int64#
+                  )^#8:Expr.Call#
+                )^#6:Expr.Call#,
+                _%_(
+                  6^#11:int64#,
+                  1^#13:int64#
+                )^#12:Expr.Call#
+              )^#10:Expr.Call#
+            )",
+      },
       TestCase{
           .source = "1 + 2 * 3 == 7 && true || false",
           .expected_ast = R"(
@@ -1039,6 +1075,18 @@ std::vector<TestCase> GetParserTestCases() {
             )",
           .enable_optional_syntax = true,
       },
+      TestCase{
+          .source = "(((10 - 3) - 2))",
+          .expected_ast = R"(
+              _-_(
+                _-_(
+                  10^#1:int64#,
+                  3^#3:int64#
+                )^#2:Expr.Call#,
+                2^#5:int64#
+              )^#4:Expr.Call#
+            )",
+      },
   };
 }