[ext-code-space][x64] Increase max code range size to 512 MB

... when external code space is enabled.

Bug: v8:11880, v8:12689
Change-Id: I0efa09a27d636df3d36d2da13ac26c7f2fedb94c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3650744Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Auto-Submit: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80594}

src/common/globals.h

@@ -308,7 +308,8 @@ constexpr size_t kMinExpectedOSPageSize = 64 * KB;  // OS page on PPC Linux
 constexpr size_t kMaximalCodeRangeSize = 128 * MB;
 constexpr size_t kMinExpectedOSPageSize = 4 * KB;  // OS page.
 #else
-constexpr size_t kMaximalCodeRangeSize = 128 * MB;
+constexpr size_t kMaximalCodeRangeSize =
+    V8_EXTERNAL_CODE_SPACE_BOOL ? 512 * MB : 128 * MB;
 constexpr size_t kMinExpectedOSPageSize = 4 * KB;  // OS page.
 #endif
 #if V8_OS_WIN
@@ -318,7 +319,9 @@ constexpr size_t kReservedCodeRangePages = 1;
 constexpr size_t kMinimumCodeRangeSize = 3 * MB;
 constexpr size_t kReservedCodeRangePages = 0;
 #endif
-#else
+
+#else  // V8_HOST_ARCH_64_BIT
+
 constexpr int kSystemPointerSizeLog2 = 2;
 constexpr intptr_t kIntptrSignBit = 0x80000000;
 #if (V8_HOST_ARCH_PPC || V8_HOST_ARCH_PPC64) && \
@@ -339,7 +342,7 @@ constexpr size_t kMinimumCodeRangeSize = 0 * MB;
 constexpr size_t kMinExpectedOSPageSize = 4 * KB;  // OS page.
 #endif
 constexpr size_t kReservedCodeRangePages = 0;
-#endif
+#endif  // V8_HOST_ARCH_64_BIT
 
 static_assert(kSystemPointerSize == (1 << kSystemPointerSizeLog2));