Removed reference to deleted assembler-arch-inl.h

src/assembler-arch-inl.h was deleted in November but it
remained in the build system. This patch also removes it from
the build system.

Change-Id: Ib384943861156d603636dc3069130cd6c5dfd4ef
Reviewed-on: https://chromium-review.googlesource.com/c/1456100
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#59396}

BUILD.gn

@@ -1557,7 +1557,6 @@ v8_source_set("v8_base") {
     "src/asmjs/asm-scanner.h",
     "src/asmjs/asm-types.cc",
     "src/asmjs/asm-types.h",
-    "src/assembler-arch-inl.h",
     "src/assembler-arch.h",
     "src/assembler-inl.h",
     "src/assembler.cc",