RFR: 8323503: x86: Shorter movptr(reg, imm) for 32-bit unsigned immediates

[Aleksey Shipilev]

We noticed in [JDK-8323497](https://bugs.openjdk.org/browse/JDK-8323497) that `movptr` optimization done in [JDK-8319406](https://bugs.openjdk.org/browse/JDK-8319406) is not covering the case of immediates that fit in 32-bit unsigned, but do not fit in 32-bit signed. In that case, we can maybe do `mov r32, imm32` and rely on x86 zero-extending 32->64 bit for us. Since `movl` encoding is smaller than sign-extending `movq`, we also save more code on most paths that [JDK-8319406](https://bugs.openjdk.org/browse/JDK-8319406) improved.

There are a few interesting conversions along the way:
  1. `intptr_t` -> `uint32_t` (this method)
  2. `uint32_t` -> `int32_t` (argument conversion for `movl`)
  3. `int32_t` -> `uint32_t` (in `emit_int32`)
 
I believe these are safe after `is_uimm32` check, but please check (sic) me on this.

Note that x86_64 matcher already does similar thing for immediates:


// Long Immediate 32-bit unsigned
operand immUL32()
%{
  predicate(n->get_long() == (unsigned int) (n->get_long()));
  match(ConL);
  ...
%}

instruct loadConUL32(rRegL dst, immUL32 src)
%{
  ...
  format %{ "movl    $dst, $src\t# long (unsigned 32-bit)" %}
  ins_encode %{
    __ movl($dst$$Register, $src$$constant);
  %}
%}


Additional testing:
 - [x] Linux x86_64 server fastdebug, `tier{1,2,3,4}`

Code sizes for `Hello World`, `-Xcomp`:


# Before
  tier1 nmethod code size         :   426208 bytes
  tier2 nmethod code size         :   462880 bytes
  tier3 nmethod code size         :   889992 bytes
  tier4 nmethod code size         :  1244448 bytes

# After
  tier1 nmethod code size         :   425768 bytes (-0.1%)
  tier2 nmethod code size         :   462400 bytes (-0.1%)
  tier3 nmethod code size         :   882072 bytes (-0.8%)
  tier4 nmethod code size         :  1236448 bytes (-0.6%)

-------------

Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/17343/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17343&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323503
  Stats: 4 lines in 2 files changed: 3 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/17343.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17343/head:pull/17343

PR: https://git.openjdk.org/jdk/pull/17343