Suppress compiler and linker warnings in v8 test binaries

VC++ complains about truncation of integer constants despite use of
static_cast. This isn't very helpful as it gives no way of suppressing
the warning in code, so this change suppresses it on the command line.

Additionally, the linker complains about importing of locally defined
functions in component builds. Until this is fixed the warnings should
be suppressed.

NOTRY=true

Review-Url: https://codereview.chromium.org/2028353004
Cr-Commit-Position: refs/heads/master@{#36695}

test/cctest/BUILD.gn

@@ -316,6 +316,18 @@ executable("cctest") {
   } else {
     deps += [ "../..:v8" ]
   }
+
+  if (is_win) {
+    # This warning is benignly triggered by the U16 and U32 macros in
+    # bytecode-utils.h.
+    # C4309: 'static_cast': truncation of constant value
+    cflags = [ "/wd4309" ]
+
+    # Suppress warnings about importing locally defined symbols.
+    if (is_component_build) {
+      ldflags = [ "/ignore:4049", "/ignore:4217" ]
+    }
+  }
 }
 
 action("resources") {

test/unittests/BUILD.gn

@@ -165,4 +165,16 @@ executable("unittests") {
   } else {
     deps += [ "../..:v8" ]
   }
+
+  if (is_win) {
+    # This warning is benignly triggered by the U16 and U32 macros in
+    # bytecode-utils.h.
+    # C4309: 'static_cast': truncation of constant value
+    cflags = [ "/wd4309" ]
+
+    # Suppress warnings about importing locally defined symbols.
+    if (is_component_build) {
+      ldflags = [ "/ignore:4049", "/ignore:4217" ]
+    }
+  }
 }