testsuite: RISC-V: Add '.option norvc' to ensure consistent results.

Add `.option norvc` to several RISC-V tests to avoid compressed
instruction generation.  This ensures consistent disassembly and
alignment behavior regardless of assembler default options.

Discussion see:
https://patchwork.sourceware.org/project/binutils/patch/20250910120916.1103023-1-jiawei@iscas.ac.cn/

gas/ChangeLog:

	* testsuite/gas/riscv/dis-partial-insn.s: Limit compressed.
	* testsuite/gas/riscv/no-relax-align.s: Ditto.
	* testsuite/gas/riscv/odd-padding.s: Ditto.
	* testsuite/gas/riscv/t_insns.s: Ditto.
	* testsuite/gas/riscv/tlsdesc.s: Ditto.

gas/testsuite/gas/riscv/dis-partial-insn.s

@@ -1,2 +1,3 @@
 target:
+	.option norvc
 	nop

gas/testsuite/gas/riscv/no-relax-align.s

@@ -1,4 +1,5 @@
 	.option norelax
+	.option norvc
 	.align 4
 	nop
 	nop

gas/testsuite/gas/riscv/odd-padding.s

@@ -1,3 +1,4 @@
+	.option norvc
 	.text
 byte:
 	nop

gas/testsuite/gas/riscv/t_insns.s

@@ -1,2 +1,3 @@
 target:
+	.option norvc
 	nop

gas/testsuite/gas/riscv/tlsdesc.s

@@ -1,3 +1,4 @@
+	.option norvc
 	.section	.tbss,"awT",@nobits
 	.global sg1
 sg1: