[clang-tidy] Prefer static_cast to c style casts

See
https://clang.llvm.org/extra/clang-tidy/checks/google-readability-casting.html
and https://google.github.io/styleguide/cppguide.html#Casting.

Change-Id: Ib5a3bb8873bc6d050c4d0abe36a3ae813bbd448a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2233987Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68301}

src/regexp/regexp-compiler.cc

@@ -775,7 +775,7 @@ static int GetCaseIndependentLetters(Isolate* isolate, uc16 character,
       if (in_special_add_set && RegExpCaseFolding::Canonicalize(cu) != canon) {
         continue;
       }
-      letters[items++] = (unibrow::uchar)(cu);
+      letters[items++] = static_cast<unibrow::uchar>(cu);
     }
   }
   DCHECK(ContainsOnlyUtf16CodeUnits(letters, items));

src/regexp/regexp-macro-assembler.cc

@@ -67,7 +67,7 @@ int RegExpMacroAssembler::CaseInsensitiveCompareUnicode(Address byte_offset1,
   DCHECK_EQ(0, byte_length % 2);
 
 #ifdef V8_INTL_SUPPORT
-  int32_t length = (int32_t)(byte_length >> 1);
+  int32_t length = static_cast<int32_t>(byte_length >> 1);
   icu::UnicodeString uni_str_1(reinterpret_cast<const char16_t*>(byte_offset1),
                                length);
   return uni_str_1.caseCompare(reinterpret_cast<const char16_t*>(byte_offset2),