[clang][driver] Enable MisExpect diagnostics flag outside of CC1

Previously we only accepted the `-fdiagnostics-misexpect-tolerance=` at
CC1, when it should have been handled identically to
`-fdiagnostics-hotness-threshold=`. It should not have been required to
pass this flag w/ `-Xclang` as reported here:
https://reviews.llvm.org/D115907#inline-1440745

Reviewed By: hans, phosek

Differential Revision: https://reviews.llvm.org/D149206

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4033,6 +4033,13 @@ static void RenderDiagnosticsOptions(const Driver &D, const ArgList &Args,
     CmdArgs.push_back(Args.MakeArgString(Opt));
   }
 
+  if (const Arg *A =
+          Args.getLastArg(options::OPT_fdiagnostics_misexpect_tolerance_EQ)) {
+    std::string Opt =
+        std::string("-fdiagnostics-misexpect-tolerance=") + A->getValue();
+    CmdArgs.push_back(Args.MakeArgString(Opt));
+  }
+
   if (const Arg *A = Args.getLastArg(options::OPT_fdiagnostics_format_EQ)) {
     CmdArgs.push_back("-fdiagnostics-format");
     CmdArgs.push_back(A->getValue());

clang/test/Driver/clang_f_opts.c

@@ -140,6 +140,10 @@
 // CHECK-PROFILE-USE-DIR: "-fprofile-instrument-use-path={{.*}}.d/some/dir{{/|\\\\}}default.profdata"
 // CHECK-PROFILE-USE-FILE: "-fprofile-instrument-use-path=/tmp/somefile.prof"
 
+// RUN: %clang -### -S -fprofile-instr-use=%t.profdata -fdiagnostics-misexpect-tolerance=10 -Wmisexpect %s 2>&1 | FileCheck %s --check-prefix=CHECK-MISEXPECT-TOLLERANCE
+// CHECK-MISEXPECT-TOLLERANCE: "-fdiagnostics-misexpect-tolerance=10"
+// CHECK-MISEXPECT-TOLLERANCE-NOT: argument unused
+
 // RUN: %clang -### -S -fvectorize %s 2>&1 | FileCheck -check-prefix=CHECK-VECTORIZE %s
 // RUN: %clang -### -S -fno-vectorize -fvectorize %s 2>&1 | FileCheck -check-prefix=CHECK-VECTORIZE %s
 // RUN: %clang -### -S -fno-vectorize %s 2>&1 | FileCheck -check-prefix=CHECK-NO-VECTORIZE %s