We currently use the class name “JSValue” for JSObjects that wrap
primitive values. This name is a common source of confusion. This patch
switches to a name that’s more clear.

In addition to manual tweaks, the patch applies the following mechanical
global replacements:

before                          | after
--------------------------------|--------------------------------------
if_valueisnotvalue              | if_valueisnotwrapper
if_valueisvalue                 | if_valueiswrapper
js_value                        | js_primitive_wrapper
JS_VALUE_TYPE                   | JS_PRIMITIVE_WRAPPER_TYPE
JSPrimitiveWrapperType          | JSPrimitiveWrapper type
jsvalue                         | js_primitive_wrapper
JSValue                         | JSPrimitiveWrapper
_GENERATED_JSVALUE_FIELDS       | _GENERATED_JSPRIMITIVE_WRAPPER_FIELDS

Change-Id: I9d9edea784eab6067b013e1f781e4db2070f807c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1672942Reviewed-by: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62337}