[lldb] support ieee_single and ieee_double gdbtypes for registers (#150268)

Some gdb remote servers send target.xml that contains 
```
<reg name='ft0' bitsize='32' type='ieee_single' dwarf_regnum='32'/>
  <reg name='ft1' bitsize='32' type='ieee_single' dwarf_regnum='33'/>
  <reg name='ft2' bitsize='32' type='ieee_single' dwarf_regnum='34'/>
  <reg name='ft3' bitsize='32' type='ieee_single' dwarf_regnum='35'/>
  <reg name='ft4' bitsize='32' type='ieee_single' dwarf_regnum='36'/>
  <reg name='ft5' bitsize='32' type='ieee_single' dwarf_regnum='37'/>
  <reg name='ft6' bitsize='32' type='ieee_single' dwarf_regnum='38'/>
  <reg name='ft7' bitsize='32' type='ieee_single' dwarf_regnum='39'/>
```

it seems like a valid and supported type in gdb. 
from gdb16.3/gdb/target_descriptions.c (could not find a way to link
it).
```
case TDESC_TYPE_IEEE_SINGLE:
	  m_type = init_float_type (alloc, -1, "builtin_type_ieee_single",
				    floatformats_ieee_single);
	  return;

case TDESC_TYPE_IEEE_DOUBLE:
	  m_type = init_float_type (alloc, -1, "builtin_type_ieee_double",
				    floatformats_ieee_double);
	  return;
```	

### Testplan

updated unittest to test this. 


Reviewers: @clayborg , @jeffreytan81 , @Jlalond

0 files changed, 0 insertions, 0 deletions