[cctest] Move cctest.cc from cctest_sources to cctest target

Both MSVC and Clang require a mainCRTStartup symbol for the cctest
executable to compile. All objects from the cctest_sources source
set are bundled into a library which does not contain this symbol.

Bug: v8:7854
Change-Id: I88cd26209114daa84574e3b20046613b1560fa98
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1357039
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Sergiy Belozorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61206}

AUTHORS

@@ -154,6 +154,7 @@ Refael Ackermann <refack@gmail.com>
 Rene Rebe <rene@exactcode.de>
 Rick Waldron <waldron.rick@gmail.com>
 Rob Wu <rob@robwu.nl>
+Robert Meijer <robert.s.meijer@gmail.com>
 Robert Mustacchi <rm@fingolfin.org>
 Robert Nagy <robert.nagy@gmail.com>
 Ruben Bridgewater <ruben@bridgewater.de>

test/cctest/BUILD.gn

@@ -6,6 +6,11 @@ import("../../gni/v8.gni")
 
 v8_executable("cctest") {
   testonly = true
+
+  sources = [
+    "cctest.cc",
+  ]
+
   deps = [
     ":cctest_sources",
   ]
@@ -57,7 +62,6 @@ v8_source_set("cctest_sources") {
     "../common/wasm/flag-utils.h",
     "../common/wasm/test-signatures.h",
     "../common/wasm/wasm-macro-gen.h",
-    "cctest.cc",
     "compiler/c-signature.h",
     "compiler/call-tester.h",
     "compiler/code-assembler-tester.h",