RFR: [backport] 8202976: Add C1 lea patching support for x86

[Roman Kennke]

> On 11/25/20 9:39 PM, Roman Kennke wrote:
>> This patch was actually missing the aarch64 parts. The original change
>> did not have it either, it only came much later with the ZGC port to
>> aarch64. I would like to add it here.
>>
>> http://cr.openjdk.java.net/~rkennke/JDK-8202976-jdk8/webrev.01/
> 
> I believe we need to protect new blocks in c1_LIRAssembler_aarch64.cpp
> with UseShenandoahGC?

Right. I'm pushing this:
http://cr.openjdk.java.net/~rkennke/JDK-8202976-jdk8/webrev.02/

Thanks,
Roman